NSRegularExpression

gistfile1.m

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        
        NSString *original = @"a\nb";
        NSLog(@"%@", original);
        NSMutableString *string = [NSMutableString stringWithString:original];
        NSRegularExpression *re = [NSRegularExpression regularExpressionWithPattern:@"\n+" options:0 error:nil];
        [re replaceMatchesInString:string options:0 range:NSMakeRange(0, [string length]) withTemplate:@""];
        NSString *result = [NSString stringWithString:string];
        NSLog(@"%@", result);
        
    }
    return 0;
}